Anticholinergics (Includes Gastrinex) ↔ Autonomic Neuropathy

Severe Potential Hazard, High plausibility

Applies to: Autonomic Neuropathy

Agents with anticholinergic activity can exacerbate many of the manifestations of autonomic neuropathy, including tachycardia, anhidrosis, bladder atony, obstipation, dry mouth and eyes, cycloplegia and blurring of vision, and sexual impotence in males. Therapy with antimuscarinic agents and higher dosages of antispasmodic agents (e.g., dicyclomine or oxybutynin) should be administered cautiously in patients with autonomic neuropathy.

Anticholinergics (Includes Gastrinex) ↔ Glaucoma

Severe Potential Hazard, High plausibility

Applies to: Glaucoma/Intraocular Hypertension

Anticholinergic agents are contraindicated in patients with primary glaucoma, a tendency toward glaucoma (narrow anterior chamber angle), or adhesions (synechiae) between the iris and lens, as well as for the elderly and others in whom undiagnosed glaucoma or excessive pressure in the eye may be present. Because anticholinergics cause mydriasis, they may exacerbate these conditions.

Anticholinergics (Includes Gastrinex) ↔ Obstructive Uropathy

Severe Potential Hazard, High plausibility

Applies to: Urinary Retention

In general, the use of anticholinergic agents is contraindicated in patients with urinary retention and bladder neck obstruction caused by prostatic hypertrophy. Dysuria may occur and may require catheterization. Also, anticholinergic drugs may aggravate partial obstructive uropathy. Caution is advised even when using agents with mild to moderate anticholinergic activity, particularly in elderly patients.

Anticholinergics (Includes Gastrinex) ↔ Reactive Airway Diseases

Severe Potential Hazard, Moderate plausibility

Applies to: Asthma

The use of systemic anticholinergics is contraindicated in the treatment of lower respiratory tract symptoms including asthma. Muscarinic receptor antagonists reduce bronchial secretions, which can result in decreased fluidity and increased thickening of secretions. However, ipratropium does not produce these effects and can be used safely in treating asthma.

Antihistamines (Includes Gastrinex) ↔ Anticholinergic Effects

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Antimuscarinics (Includes Gastrinex) ↔ Myasthenia Gravis

Severe Potential Hazard, Moderate plausibility

Applies to: Myasthenia Gravis

Because antimuscarinic agents have anticholinergic effects, they are contraindicated in patients with myasthenia gravis. Their use may be appropriate to reduce adverse muscarinic effects caused by an anticholinesterase agent.

References

Antiperistaltic Agents (Includes Gastrinex) ↔ Infectious Diarrhea

Severe Potential Hazard, High plausibility

Applies to: Infectious Diarrhea/Enterocolitis/Gastroenteritis

The use of drugs with antiperistaltic activity (primarily antidiarrheal and antimuscarinic agents, but also antispasmodic agents such as dicyclomine or oxybutynin at high dosages) is contraindicated in patients with diarrhea due to pseudomembranous enterocolitis or enterotoxin-producing bacteria. These drugs may prolong and/or worsen diarrhea associated with organisms that invade the intestinal mucosa, such as toxigenic E. coli, Salmonella and Shigella, and pseudomembranous colitis due to broad-spectrum antibiotics. Other symptoms and complications such as fever, shedding of organisms and extraintestinal illness may also be increased or prolonged. In general, because antiperistaltic agents decrease gastrointestinal motility, they may delay the excretion of infective gastroenteric organisms or toxins and should be used cautiously in patients with any infectious diarrhea, particularly if accompanied by high fever or pus or blood in the stool. Some cough and cold and other combination products may occasionally include antimuscarinic agents for their drying effects and may, therefore, require careful selection when necessary.

References

Antihistamines (Includes Gastrinex) ↔ Asthma/Copd

Moderate Potential Hazard, Moderate plausibility

Applies to: Asthma, Chronic Obstructive Pulmonary Disease

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

Antihistamines (Includes Gastrinex) ↔ Cardiovascular

Moderate Potential Hazard, Moderate plausibility

Applies to: Cardiovascular Disease, Hyperthyroidism, Hypotension

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

Antihistamines (Includes Gastrinex) ↔ Renal/Liver Disease

Moderate Potential Hazard, High plausibility

Applies to: Liver Disease, Renal Dysfunction

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

Antimuscarinics (Includes Gastrinex) ↔ Gastric Ulcer

Moderate Potential Hazard, Low plausibility

Applies to: Bleeding

Antimuscarinic agents may cause a delay in gastric emptying and possibly antral stasis in patients with gastric ulcer. Therapy with antimuscarinic agents should be administered cautiously to patients with gastric ulcer.

Antimuscarinics (Includes Gastrinex) ↔ Gastroesophageal Reflux

Moderate Potential Hazard, Moderate plausibility

Applies to: Gastroesophageal Reflux Disease

Antimuscarinic agents decrease gastric motility and relax the lower esophageal sphincter which promotes gastric retention and can aggravate reflux. These drugs should be administered cautiously in patients with gastroesophageal reflux or hiatal hernia associated with reflux esophagitis.

Antimuscarinics (Includes Gastrinex) ↔ Ulcerative Colitis

Moderate Potential Hazard, Moderate plausibility

Applies to: Inflammatory Bowel Disease

Antimuscarinic agents may suppress intestinal motility and produce paralytic ileus with resultant precipitation of toxic megacolon. These drugs should be administered cautiously to patients with ulcerative colitis.

Anticholinergics (Includes Gastrinex) ↔ Hyperthyroidism

Minor Potential Hazard, Low plausibility

Applies to: Hyperthyroidism

In general, agents with anticholinergic activity may exacerbate hyperthyroidism. Therapy with anticholinergics should be administered cautiously in patients with hyperthyroidism. Thyroid levels should be monitored if usage is prolonged.

Antimuscarinics (Includes Gastrinex) ↔ Diarrhea

Minor Potential Hazard, Moderate plausibility

Applies to: Diarrhea

Diarrhea may be a symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy. Antimuscarinic agents may further aggravate the diarrhea. Therefore, these drugs should be administered cautiously in patients with diarrhea.

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